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Seagrass seed‐based restoration has been developed in several places worldwide, but disturbance at the vulnerable initial stages of seedling recruitment has proved to be a major bottleneck to successful restoration. A detailed investigation of seagrass seedling survival and growth at the earliest stages of seedling development is an important contribution to developing techniques to improve seedling establishment and survival. Here, we investigated the early seedling development of Posidonia australis and P. sinuosa as well as quantifying the variation in seedling survival and development under different seed‐based restoration methods. Early seedling development was documented in indoor aquaria during the first month after fruit dehiscence. In the second ex situ experiment, we determined the effects of three different restoration methods (surface sowing, seedling planting, and planting inside a hessian bag) on seedling survival and development over the first 2 months of life. In the first experiment, a primary root with the first root hairs developed after 7 days. After 1 month, roots were 20–60 mm in length, firmly establishing the seedling into the sediment. Compared to surface sowing, seedling planting and hessian bag restoration treatments did not significantly affect survival for P. australis but increased seedling mortality in P. sinuosa, although growth was greater (shoot and root lengths were approximately 50 and 40% longer, respectively). These aquarium‐scale experiments suggest that planting methods would enhance seedling establishment at larger scales in some species, promoting restoration of damaged seagrass habitats. [ABSTRACT FROM AUTHOR]

Seagrasses provide key ecological services in coastal marine and estuarine environments. Human activities and environmental changes affect seagrasses compromising their structure and functioning. In this context, seagrass restoration has become a worldwide priority to halt and reverse degradation and to recover ecosystem functionality and associated services. Here, we investigate the sexual reproduction of Posidonia oceanica by describing the flowering and fruiting process. Furthermore, we compare the structural (survival and shoot density) and functional (daily leaf production, DLP) descriptors of seedlings with those derived from a P. oceanica transplantation performed through cuttings to assess their feasibility as an integrative source of vegetal material for restoration purposes. Despite many initial flowers and fruits, a small number of mature fruits are produced, confirming the low reproductive success of the phanerogam. A comparison of structural and functional features showed that seedlings and cuttings showed similar survival and shoot density rates after more than 2 years. In addition, DLP showed that seedlings increased in leaf length over the study period, reaching a similar value registered by cuttings. The study demonstrates the effectiveness of using seedlings in restoration efforts. It also emphasizes the importance of exploring P. oceanica reproductive ecology to better understand temporal and spatial variations in flowering, as well as fruiting success, at local and basin scales. [ABSTRACT FROM AUTHOR]

Seagrasses provide various ecosystem functions in coastal areas of the world. In the Mediterranean Sea, Posidonia oceanica is an endemic species threatened by several activities despite being protected by national and international laws. Currently, several transplanting initiatives have been carried out using different methods, among which those including seeds and seedlings are considered the most ecological and low‐cost ones. Beach‐cast fruits and seeds can be found in spring and their appearance can easily be reported, through a citizen science approach, by the community. One of the obstacles in using these methods is identifying the best substrate in which to place P. oceanica seeds to facilitate root adhesion of the seedlings prior to their transplantation into the sea. In the present study, we analyzed, using a 3D surface optical microscope, the roughness of natural rocks to identify the availability of specific roughness ranges suitable for adhesion and root anchoring of P. oceanica seedlings. Conventional roughness parameters and roughness power spectral density were calculated for the inner and outer surfaces of 9 different rock samples. Among the rock samples examined, the calcarenitic ones and in particular marsala calcarenite, due to the presence of the "ideal roughness for seedlings" can be considered one of the best consolidated substrates to be used for the construction of ad hoc devices on which plantlet of P. oceanica can grow for the purpose of restoration. [ABSTRACT FROM AUTHOR]

Few restoration studies have quantified the recovery of the donor meadow. We evaluated the recovery of a monospecific donor meadow of Halodule wrightii, the second most commonly used transplanting species, and assessed the possible effect of 24 plots of 1 m2 placed in an approximately 3,400 m2 large monospecific meadow with a mean cover of 45%, foliar shoot density of 1,280 shoots/m2, and 16 cm canopy height. Extraction densities were 9, 25, 64, and 121 small‐sized extraction cores (4.5 cm diameter, 20 cm depth), with control and procedural control without extractions (N = 4 per treatment). After 6 months, even the plots with the highest extraction densities recovered, as indicated by the shoot number in the extraction areas and seagrass cover in the plots approaching the levels in the controls. The recovery occurred under the environmental conditions: light availability (22,000 ± 51 lx), relatively stable sediments (0.8–1.16 cm) with a fine sandy composition (mean grain diameter, D50: 0.5 ± 0.22 mm), and low organic matter (0.22 ± 0.012%). The recolonization rate was 1–3 shoots per month in the 4.5 cm diameter extraction areas, independent of the extraction level. Thus, approximately 20% of the H. wrightii meadow (corresponding with 121 cores/m2) could be extracted in our study area. This high extraction intensity can be attributed to the adequate selection of donor species, meadow, and size of the planting unit. [ABSTRACT FROM AUTHOR]

The extent of seagrasses has declined globally, with restoration through transplantation seen as an important tool for reversing population loss, yet restoration studies for African seagrass species are scarce. This study investigated the use of different planting patterns (straight‐line, compact, and star) and core sizes (11, 18, and 25 cm Ø) in transplanting ecotypes (intertidal and subtidal) in the predominantly open Knysna and temporarily closed Klein Brak estuaries in South Africa. Cores of the endangered seagrass, Zostera capensis, were transplanted in two experimental repeats per ecotype and core size along transects to investigate survival of plants post‐transplant. No significant differences were observed among core sizes, patterns, or ecotypes in the Knysna Estuary, but cores with the compact pattern had better survival rates in the Klein Brak Estuary. Holes left by the smallest cores in donor sites recovered faster through sediment deposition compared to larger holes. Our study demonstrated that seagrass restoration in South Africa is challenging due to limited suitable habitats and strong environmental variability in estuarine ecosystems. It is important that careful consideration, including of genomic diversity and population structure, as well as ecological similarity between donor and recipient populations must be made for each restoration site when assessing its restoration potential. Effective "no‐take bait zones" and upstream catchment management will be important for protecting potential donor meadows. [ABSTRACT FROM AUTHOR]

The restoration of seagrass habitats is a relatively young field with several successful restoration attempts highlighting the feasibility of large‐scale restoration. Successful restoration of seagrass habitats requires an understanding of the most appropriate techniques to use for the target species and local conditions of restoration sites, however, there are currently limited studies on Zostera muelleri. Here, we conduct field trials to explore the use of seed‐ and shoot‐based restoration approaches for Z. muelleri in Victoria, Australia. We assessed the feasibility of collecting and germinating seeds in the field for restoration purposes and trialed the success of four shoot‐based transplanting techniques. We found that seed collections for Z. muelleri were highly successful and scalable, with seed collection rates improving from 489 to 1,939 seeds/hour over 2 years. In addition, in situ seedling germination increased from a maximum of 10.80–25.25% over 2 years. In contrast, shoot‐based restoration approaches were more variable, with plants transplanted with their sediment‐intact outperforming all bare‐rooted approaches. Shoot‐based transplanting approaches appear to have more limited application, but may be appropriate for some restoration sites, or used in combination with seeds to achieve the best restoration outcome. Seed‐based approaches have the potential to be viable and scalable for Z. muelleri given that large numbers of seeds can be collected and stored for at least 7 months before successfully germinating in the field. However, further studies are required to overcome the seedling survival bottleneck (approximately 4 months from emergence) and further increase in situ germination rates. [ABSTRACT FROM AUTHOR]

Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost‐effectiveness of restoration projects. We aim to optimize restoration of the threatened seagrass Posidonia australis by identifying the traits of donor material that best predict survival and establishment. To avoid collecting donor material from threatened populations, a recent restoration method focuses on using naturally detached fragments of P. australis collected from the shoreline, which are stored in outdoor tanks prior to planting. Here, we examine 10 morphological traits of P. australis fragments and other variables relating to collection method to identify which traits best predicted survival after replanting. Fragments with more shoots and less dead tissue (necrosis) in their leaves had higher survival 1 year after planting. Fragments that were stored longer in tanks prior to replanting had significantly higher survival rates. These results can refine the selection for donor material used in restoration and optimize the recently developed restoration technique for P. australis using beach‐cast seagrass material. [ABSTRACT FROM AUTHOR]

Seagrass restoration requires information on a range of factors including site environmental conditions, appropriate planting techniques, and the identification of sites most likely to support seagrass. To address the question of where to focus restoration efforts, a key first step is to identify trends in the spatio‐temporal distribution of seagrasses to identify areas of persistence, loss, and recent gains. Areas of recent recovery (and adjacent areas), can then be targeted by practitioners for assisted recovery and restoration, whilst areas of persistent loss can be avoided. Here we identified the contemporary distribution, density, and species composition of seagrass ecosystems (using Sentinel 2 imagery and supervised object‐based imagery analysis) and integrated these data with historic extents to identify spatio‐temporal trends in seagrass distribution in Western Port, Victoria, Australia. Contemporary classifications demonstrated acceptable accuracies (Overall Accuracy 0.77–0.85, User Accuracy 0.76–0.97) and predicted a contemporary seagrass extent of 222 km2; with 48 km2 of low‐density recovery predicted to have occurred since 1999. Comparisons with historical seagrass extents indicated some seagrass recovery since large‐scale losses in 1983, although some areas of loss were also present. Recovery included a net gain of approximately 95 km2 in the past 20 years and an eastward range expansion; suggesting environmental conditions have improved and are now conducive for restoration efforts in some areas. Results demonstrate that accurate, low‐cost, remote sensing of seagrass ecosystems is possible and show how understanding spatio‐temporal trends can guide the spatial allocation of resources by prioritizing areas for restoration where recovery is beginning to occur. [ABSTRACT FROM AUTHOR]

Semi‐natural grasslands invaded by the legume Lupinus polyphyllus need the introduction of target species in order to promote highly endangered native target plant communities. However, which techniques are best suited to achieve both invader control and the introduction of target species at the same time? Few studies have investigated restoration techniques that support native plant communities in mountain meadows and control the invader simultaneously. We employed the restoration techniques seed bank activation and green hay transfer in combination with manual removal of the invasive L. polyphyllus on three types of grassland (Nardus grassland, mesic and wet mountain hay meadows) in the low mountain ranges of the Rhön UNESCO Biosphere Reserve in central Germany. Vegetation reacted differently to specific measures depending on the type of grassland. L. polyphyllus cover could be effectively reduced by L. polyphyllus removal in Nardus grassland and mesic hay meadow sites, but not in wet meadows. In Nardus grassland, the cover of target species was lowered by the application of green hay. The target species cover of wet mountain hay meadows declined in response to seed bank activation. When restoring mountain meadows, restoration practitioners should thus first consider the specific vegetation types. As our study indicates that target mountain meadow species may react negatively to restoration measures in the short term, the long‐term effects of the application of green hay should be studied. [ABSTRACT FROM AUTHOR]

Restoring habitats degraded by intensive agriculture is challenging, and the resulting communities often have lower quality and host fewer species than reference ecosystems. To improve restoration outputs, we need to understand what limits both establishment and performance of target species in restored populations. In this study, we focused on grassland restoration with regional seeds and compared the performance of two target herbs, Betonica officinalis and Centaurea jacea, between restored and reference populations. We also measured plant functional traits and environmental characteristics to understand which parameters affect population performance. Individual plants of both species were smaller in restored populations, which indicates reduced performance. Leaves of plants from restored populations contained more δ15N and, in Betonica, also less nitrogen and higher C:N ratio, which suggests that the performance of the target species may be limited by nitrogen. Nitrogen limitation of all restored communities was further corroborated by the low N:P ratio of bulk biomass. In Centaurea, we also recorded massive herbivory damage in restored populations, which likely further reduced this species' performance in restored meadows. In summary, target plants in restored populations showed lower performance than conspecifics in reference sites, probably due to nutrient imbalance (low nitrogen availability) and excessive herbivory damage. [ABSTRACT FROM AUTHOR]

Tree encroachment threatens the biodiversity and ecological functioning of grasslands worldwide. Reversing effects of encroachment requires not only removing trees, but limiting subsequent invasions, which can stall grassland reassembly. We quantified rates and patterns of conifer reinvasion of mountain grasslands (meadows) in western Oregon, 7 and 15 years after experimental tree removal with or without burning. We assessed frequency (percentage of 100 m2 subplots) and density of reinvading trees in six 1‐ha plots as a function of burn treatment, abundance in the adjacent forest (a proxy for seed availability), and distance to or orientation of forest edges. After 15 years, frequency and density of colonists varied widely among plots (24–57% of subplots and 60–250 trees/ha, respectively), but burning had no effect on either measure. Abies grandis, which dominated adjacent forests, was the principal invader. Colonization by less‐common Pinus contorta and A. procera was correlated with species' density and basal area in adjacent forests, suggesting that establishment was seed limited. Annualized rates of invasion were similar between early and late sampling intervals (9–10/trees/ha). Establishment was generally greater along the forested edges of plots (0–10 m) than in the core (10–50 m). Prominence of shade‐tolerant A. grandis along northerly‐facing edges suggests strong microclimatic controls on establishment. In sum, tree removal, with or without prescribed fire, is successful in reversing effects of conifer encroachment. Despite abundant seed rain, reinvasion is slow and spatially restricted. Periodic hand removal of colonizing trees, while they are small, can be done efficiently and economically. [ABSTRACT FROM AUTHOR]

Seagrass meadows play a key role in the provisioning of ecosystem goods and services. These systems are extremely vulnerable to multiple anthropogenic impacts. Therefore, there is an urgent need to develop new techniques to efficiently restore degraded seagrass meadows. Here we tested the efficacy and efficiency of a new technique of seagrass transplant (Cymodocea nodosa) using biodegradable containers. We investigated the effects of this transplant technique in the Adriatic Sea comparing the transplanted seagrass meadows with adjacent donor seagrass meadows and bare sediments used as control. We assessed the recovery rates and the ecological implications of this transplant on key ecosystems functions, including the biomass and detritus provision to local biological communities, and the effects on the biodiversity of the associated benthic fauna. Our results show that this restoration technique was successful, enabling the seagrass survival (approximately 30%) even in high‐energy conditions occurring in winter. The sediments hosting the transplanted seagrasses showed an increase of trophic availability and of rates of organic matter cycling. Despite this, 1 year after the transplant, the abundance and biodiversity of meiofaunal assemblages in the restored seagrasses were still lower than in donor seagrass meadows. These results indicate that the restoration process of seagrass meadows can take a long time, and that a multilevel approach (including the analysis of biodiversity and of the sedimentary processes and biogeochemical cycles) is needed to assess the success of restoration actions in these habitats. [ABSTRACT FROM AUTHOR]

The restoration of a threatened type of seminatural grassland—the Baltic Boreal coastal meadows—began in Estonia in 1997. The main causes of degradation of these communities were land abandonment and overgrowth by reed. In 2015, we resurveyed 14 sites and classified as (1) permanently managed or (2) restored before 2005, or (3) after 2005. In 2015, all sites were managed under the EU agri‐environmental scheme and classified as permanently managed or restored before or after 2005. The resurvey focused on assessment of the long‐term success of restoration, comparing the vegetation parameters of restored meadows with permanently managed meadows (which were considered as reference). Our study revealed that historical management patterns have an impact on the species richness of these habitats, as more species were found in historically mown meadows, even if the sites were restored by grazing. However, species richness was not an important indicator of coastal meadow recovery. The best indicators of restoration success are evenness and coverage of low‐lying, light‐demanding, salt‐tolerant, wintergreen, cryptophyte, and hemicryptophyte plant species. Phragmites australis is a good indicator species for the habitat, as its abundance indicates poor habitat quality. The study indicated that the recovery of coastal meadow habitat from abandonment requires more than 15 years of restoration activities, and suggested the 3‐year restoration period covered by conservation measures and funds is not enough. Therefore, we recommend that agri‐environmental schemes should support additional restoration activities for recently restored meadows which are entering the management scheme. [ABSTRACT FROM AUTHOR]

Seagrass meadows are habitat for an abundance and diversity of animal life, and their continuing global loss has focused effort on their restoration. This restoration not only aims to re‐establish the structure of the seagrass, but also to restore its function, particularly as habitat. The success of seagrass restoration is typically measured by the recovery of aboveground structure, but this ignores the important role of the belowground component of seagrass ecosystems, which may not recover at the same rate, and is equally important for faunal communities. We quantify infaunal communities (abundance, richness, and composition) within expanding plots of restored seagrass, and relate their change to the recovery of belowground seagrass biomass and sediment properties. We found that infaunal abundance and composition converged on that found in natural seagrass within 2 years, while the overall infaunal richness was not affected by habitat. The carbon content of surface sediments also recovered within 2 years, although recovery of belowground biomass and sediment grain size took 4 to 6 years. These results suggest that the structure of recovering seagrass habitats may not need to attain that of natural meadows before they support infauna that is comparable to natural communities. This pace and effectiveness of recovery provides some optimism for future seagrass restoration. [ABSTRACT FROM AUTHOR]

Seagrass ecosystems have suffered significant declines globally and focus is shifting to restoration efforts. A key component to successful restoration is an understanding of the genetic factors potentially influencing restoration success. This includes understanding levels of connectivity between restoration locations and neighboring seagrass populations that promote natural recovery (source and sink populations), the identification of potential donor populations, and assessment of genetic diversity of restored meadows and material used for restoration. In this study, we carry out genetic surveys of 352 individuals from 13 populations using 11 polymorphic microsatellite loci to inform seagrass restoration activities by: (1) understanding levels of genetic and genotypic diversity within meadows; and (2) understanding genetic structure and patterns of connectivity among these meadows to determine which source sites may be most appropriate to assist recovery of three restoration sites. The study identified high genotypic diversity within the locations analyzed from the Port of Gladstone and Rodd's Bay region, indicating sexual reproduction is important in maintaining populations. Overall, we detected significant genetic structuring among sites with the Bayesian structure analysis identifying genetic clusters that largely conformed to a northern, central, and southern region. This suggests limited gene flow between regions, although there does appear to be some connectivity within regions. The hydrodynamic models showed that seeds were largely locally retained, while fragments were more widely dispersed. Limited gene flow between regions suggests donor material for restoration should be sourced locally where possible. [ABSTRACT FROM AUTHOR]

The role of herbivorous fish in threatening marine forests of temperate seas has been generally overlooked. Only recently, the scientific community has highlighted that high fish herbivory can lead to regime shifts from canopy‐forming algae to less complex turf communities. Here, we present an innovative herbivorous fish deterrent device (DeFish), which can be used for conservation and restoration of marine forests. Compared to most traditional fish exclusion systems, such as cages, the DeFish system does not need regular cleaning and maintenance, making it more cost‐efficient. Resistance of DeFish was tested by installing prototypes at different depths in the French Riviera and in Montenegro: more than 60% of the devices endured several years without maintenance, even if most of them were slightly damaged in the exposed site in Montenegro. The efficacy of DeFish in limiting fish herbivory was tested by an exclusion experiment on Cystoseira amentacea in the French Riviera. In a few months, the number of fish bite marks on the seaweed was decreased, causing a consequent increase in algal length. The device here presented has been conceived for Mediterranean canopy‐forming algae, but the same concept can be applied to other species vulnerable to fish herbivory, such as kelps or seagrasses. In particular, the DeFish design could be improved using more robust and biodegradable materials. Innovative engineering systems, such as DeFish, are expected to become useful tools in the conservation and restoration of marine forests, to complement other practices including active reforestation, herbivore regulation, and regular monitoring of their status. [ABSTRACT FROM AUTHOR]

The use of Technosols for the restoration of limestone quarries overcomes the usual "in situ" scarcity of soil and/or its poor quality. The use of mine spoils, improved with mineral and/or organic amendments, could be an efficient and environmentally friendly option. Properly treated sewage sludge from urban wastewater treatment plants could be a suitable organic amendment and fertilizer (rich in N and P) whenever its pollutant burden is low (heavy metals and/or organic pollutants). Its appropriate use could improve essential soil physical and chemical properties and, therefore, promote key ecosystem services of restored areas, such as biomass production and carbon sequestration, as well as biodiversity and landscape recovery. However, the mid‐term impacts of these restoration practices on soil functioning and their services have rarely been reported in the available literature. In this study we assess the mid‐term effects (10 years) of the use of sewage sludge as a Technosol amendment on soil organic carbon (SOC), nutrient status, and plant development in several restored quarries. Soils restored using sewage sludge showed a threefold increase in SOC compared to the corresponding unamended ones, despite the moderate sludge dosage applied (below 50 tonnes/ha). Plant cover was also higher in amended soils, and recruitment was not affected by sludge amendment at these doses. This study demonstrates that, used at an appropriate rate, sewage sludge is a good alternative for the valorization of mine spoils in quarry restoration, improving some important regulatory ecosystem services such as carbon sequestration, without compromising woody plant encroachment. [ABSTRACT FROM AUTHOR]

Grassland restoration has become a key tool in addressing the drastic losses of seminatural grassland since the mid‐twentieth century. This study examined the restoration by green hay transfer of upland hay meadows, a particularly scarce and vulnerable habitat, over an 11‐year chronosequence. The community composition of 18 restoration meadows was compared with that of donor reference sites in two study areas in the Pennine region of northern England. The study investigated: differences in community composition between donor and restoration meadows; transfer of upland hay meadow target species; and the effect of time and isolation from neighboring meadows on the community composition of the restoration meadows. Results showed that restoration meadows differed from donor meadows in that some target species were easily transferred whilst others were not found in the restoration meadows, or were at low levels of cover. Time had a significant effect on the community composition of the restoration meadows, but the similarity between restoration sites and donor sites did not increase with time, and the effect of isolation was not significant. The study showed that the green hay transfer method increases botanical diversity and is an important first step in meadow restoration. However, further restoration activity, such as seed addition, is likely to be required if restoration sites are to resemble closely the reference donor sites. [ABSTRACT FROM AUTHOR]

Seed represents a potentially ecologically sustainable source of planting units for restoring seagrasses, particularly for seagrasses where transplanting negatively impacts donor beds. However, newly germinated seeds may be nutrient limited as their underdeveloped root systems may constrain capacity to access sediment-based resources. We conducted a study in land-based aquaculture tanks to determine whether early growth of newly germinated Posidonia australis seedlings could be enhanced by adding inorganic nutrients to the sediment. Sediments were supplemented with nitrogen and phosphorus in a factorial design (no nutrients, N, P, N + P). Shoot survival, whole shoot biomass, root morphology, root architecture, and nutrient concentration of seedlings were assessed monthly for the first 4 months after germination. More than 90% of seedlings survived during the 4 months of the experiment, irrespective of nutrient treatment. Growth of P. australis seedlings was not enhanced by addition of N or P to the sediment despite nutrient uptake occurring. Seedling growth was found to be more dependent on seed nutrient reserves rather than external nutrient sources for at least the first 4 months after germination. Adding inorganic nutrients to the sediment also significantly reduced the development of the seedling root system in terms of biomass, length, and density of lateral root branches. This study demonstrated that inorganic nutrient supplements constrain root development and therefore capacity for successful anchorage of seagrass seedlings, and pose a significant limitation on seedling establishment when transferred to the field, as well as potentially limiting natural and transplanted seedling establishment in eutrophic sediments. [ABSTRACT FROM AUTHOR]